Gaseous electric discharge lamp



April 4, 1939. R, ROMPE 2,153,005

GASEOUS ELECTRIC DISCHARGE LAMP Original Filed June 14, 1935 INVENTOR A ORNEY Patented Apr. 4, 1939 PATENT OFFICE GASEOUS ELECTRIC DISCHARGE LAMP Robert Rompe, Berlin, Germany, assignor to General Electric Company, a corporation of New York Application June 14, 1935, Serial No. 26,674 Renewed November 16, 1938 In Germany June 25, 1934 4 Claims.

The present invention relates .to gaseous electric discharge lamps generally.

The object of the invention is to provide a highly eflicient gaseous electric discharge lamp emitting light which closely approximates daylight. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description.

In accordance with this object the gaseous electric discharge lamp comprises a tubular quartz container having a starting gas therein, such as argon, kryptdh, xenon, or the like, and having an electrode at each end thereof consisting of tellurium. The discharge current in the lamp during the operation thereof is such that the container temperature is approximately 750 C. or more and the tellurium vapor is at a pressure ofapproximately 0.1 mm. or more. Such a lamp is highly efficient and the spectrum of the light emitted thereby closely approximates that of dayl'ght. In the drawing accompanying and forming rt of this specification a lamp embodying the invention is shown in a side elevational, partly sectional view.

Referring to the drawing the lamp comprises an elongated, tubular container I having an electrode chamber 2 at each end thereof. Said container I is sealed and consists of quartz. Each of said electrode chambers 2 has a quantity 4 of tellurium therein which is crystalline in structure when cool and which changes to a liquid when heated during the operation of the lamp.

A currentTEad 3 passes through the wall of the fixed, starting gas therein, such as krypton, xenon or argon, or mixtures thereof.

The efficiency of the above described lamp increases as the current load, the container temperature and the vapor pressure therein increases. For example, when a discharge current of sufficient strength to heat the container I to a temperature of approximately 750 C. and to raise the telluriumvapor to a pressure of about 0.1 mm. is used the lamp has an efficiency of about 24 lumens per watt. When\ the current strength is increased to the point that the container temperature is 1000 C. and the tellurium vapor pressure is about 1 mm. the lamp has an efliciency of about 40 lumens per watt. When the current strength is such that the container temperature is 1100 C. and the tellurium vapor pressure is about 10 mm. the efliciency of the lamp is about lumens per watt. This last example represents about the upper limit of efficiency of the lamp since at higher temperatures gases diffuse through the walls of the quartz container. The container temperature should be greater than 750 C. however since the light emitted by the lamp is bluish or true blue in color below this container temperature.

The above described lamp is also useful in therapeutic work since it emits ultra-violet rays of long wave length. When desired, fluorescent materials are used with the lamp to transform the ultra-violet light into visible light to supplement the visible light emitted by the lamp. When desired the lamp is provided with a heat conservator to reduce the heat losses therefrom to a minimum and to improve the efficiency of the lamp.

While I have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in'its use and operation may be made by thoseskilled in the art without departing from the broad spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. An electric discharge lamp comprising an elongated, sealed container of material transparent to light rays, an electrode chamber at each end thereof, a quantity of luminosity producing, vaporizable telluriumin each of said electrode chambers, a current lead terminating in the tellurium in each of said electrode chambers and a fixed, starting gas in said container, said current leads being capable of conducting sufficient electrical energy to said lamp to maintain a tellurium vapor pressure therein greater than 0.1 mm.

2. An electric discharge lamp comprising an elongated, sealed container of material transparent to light rays, an electrode chamber at each end thereof, a quantity of luminosity producing, vaporizable tellurium in each of said electrode chambers, a current lead terminating in the tellurium in each of said electrode chambers and a fixed, starting gas in said container, said current leads being capable of conducting sufficient electrical energy to said lamp to maintain the container at a temperature of more than about 750 C. and to raise the tellurium vapor to a pressure giving a luminous efliciency of more than about 24 lumens per watt.

3. An electric discharge lamp comprising an elongated, sealed container of material transparent to light rays, an electrode chamber at each end thereof, a quantity of luminosity producing, vaporizable tellurium in each of said electrode chambers, a current lead terminating in the tellurium in each of said electrode chambers and a fixed, starting gas in said container, said current leads being capable of conducting sufficient electrical energy to said lamp to maintain the container at a temperature of between about in, a charge of rare gas in said container and a quantity of tellurium metal in said container, said lamp being constructed to operate with an electric discharge at a temperature at which the tellurium vapor in the path of said discharge has a sufliciently high density to cause the characteristic spectrum of said vapor to predominate inthe light emitted by said lamp.

ROBERT ROMPE. 

